Room lighting may be used by modulation for transferring high data rates. In laboratory experiments, powerful light diode (LED) lighting systems such as an Osram OSTAR E3B LED module have proved to be suitable.
A powerful amplifier had to be developed for the OSTAR E3B LED module, which despite the low input impedance of the LED module meets the extremely high demands in respect of output power, bandwidth and linearity. Additionally, a compact design likewise plays an important role in enabling the LED module including the amplifier to be integrated into the room lighting.
The impedance of a light diode is very small across the entire frequency range from a few hundred kHz to several tens of MHz.
If conventional high-frequency amplifiers with an output impedance of 50 ohms are used to actuate the LED, their output impedance must be adjusted across the entire frequency range to the very small input impedance of the LED using impedance transformers. Such impedance transformers in the form of transformers are expensive, narrow-band and large. Operational amplifiers which can be obtained especially for the double-digit MHz range have a relatively low output impedance of approximately 5 ohms, and the frequency range and linearity are not large enough for this.